<em>Fibroblast</em> <em>growth</em> <em>factor</em> (FGF) signaling plays critical roles in key biological processes ranging from embryogenesis to wound healing and has strong links to several hallmarks of cancer. Genetic alterations in FGF receptor (FGFR) family members are associated with increased tumor <em>growth</em>, metastasis, angiogenesis, and decreased survival. JNJ-42756493, erdafitinib, is an orally active small molecule with potent tyrosine kinase inhibitory activity against all four FGFR family members and selectivity versus other highly related kinases. JNJ-42756493 shows rapid uptake into the lysosomal compartment of cells in culture, which is associated with prolonged inhibition of FGFR signaling, possibly due to sustained release of the inhibitor. In xenografts from human tumor cell lines or patient-derived tumor tissue with activating FGFR alterations, JNJ-42756493 administration results in potent and dose-dependent antitumor activity accompanied by pharmacodynamic modulation of phospho-FGFR and phospho-ERK in tumors. The results of the current study provide a strong rationale for the clinical investigation of JNJ-42756493 in patients with tumors harboring FGFR pathway alterations. Mol Cancer Ther; <em>16</em>(6); 1010-20. ©2017 AACR.

OBJECTIVE

To evaluate mechanisms that contribute to tissue repair and tissue remodeling in Crohn's disease (CD).

BACKGROUND

Transforming growth factor-betas (TGF-betas) are involved in different chronic inflammatory disorders. They function by binding to two receptors, type I (TbetaR-I) subtype ALK5 and type II (TbetaR-II), which are concomitantly required for signal transduction.

METHODS

Tissues were obtained from 18 patients with CD (10 female patients, 8 male patients, median age 38.7 years [range 16 to 58 years]) undergoing surgery because of CD-related complications. Tissue samples of 18 healthy organ donors (10 female subjects, 8 male subjects, median age 50.3 years [range 15 to 65 years]) served as controls. The expression and localization of TGF-beta1, TGF-beta2, TGF-beta3, TbetaR-IALK5, TbetaR-II, and TbetaR-III were studied by Northern blot analysis, in situ hybridization, and immunohistochemistry.

RESULTS

On Northern blot analysis, 94% of the CD samples exhibited enhanced TGF-beta1, TGF-beta3, and TbetaR-II mRNA expression compared with controls. TGF-beta2 was increased in 72%, TbetaR-IALK5 in 72%, and TbetaR-III in 82% of the patients with CD. On in situ hybridization and immunohistochemical analysis, TGF-beta1, TbetaR-IALK5, and TbetaR-II were seen to be colocalized in the lamina propria cells and in the lymphocytes closest to the luminal surface, but also in the remaining epithelial cells, and in fibroblasts of CD tissue samples.

CONCLUSIONS

The concomitant overexpression of TGF-betas and their signaling receptors in CD points to a potential role of these regulatory molecules in the pathophysiology of CD. Activation of TGF-beta-mediated pathways might promote the repair of mucosal injury by enhancing the process of reepithelization, but might also contribute to extracellular matrix generation and subsequently to intramural fibrosis and intestinal obstruction.

Epithelial-mesenchymal interactions play an important role in controlling epidermal morphogenesis and homeostasis but little is known about the mechanisms of these interactions. To examine whether diffusible <em>factors</em> produced by <em>fibroblasts</em> and/or keratinocytes support epidermal morphogenesis and basement membrane formation, organotypic keratinocyte monocultures were established in media collected either from organotypic <em>fibroblast</em> or keratinocyte-monocultures or from keratinocyte-<em>fibroblast</em> cocultures, and the expression of keratin 10, <em>16</em>, and 17 and basement membrane components (types IV and VII collagen, laminin 5, nidogen, BP 180, LAD-1) were examined. We found that diffusible <em>factors</em> released by keratinocytes were not sufficient to support the establishment of normalized epidermal phenotype and deposition of basement membrane components in contrast to <em>fibroblast</em>- or keratinocyte/<em>fibroblast</em>-derived <em>factors</em>. Keratinocytes appear to affect the spectrum of secreted soluble <em>factors</em>, as keratinocyte/<em>fibroblast</em>-derived <em>factors</em> were more effective to accomplish continuous linear deposition of laminin 5 and of nidogen. The finding that released amounts of keratinocyte <em>growth</em> <em>factor</em> and granulocyte macrophage colony stimulating <em>factor</em> were not sufficient to fully support epidermal morphogenesis and deposition of basement membrane components is suggestive for the involvement of other released diffusible <em>factors</em>. Generation of organotypic keratinocyte monocultures in the presence of <em>fibroblast</em>- or keratinocyte/<em>fibroblast</em>-derived soluble <em>factors</em> resulted in enhanced expression of keratins K<em>16</em> and K17 and the absence of type IV collagen. This observation indicates that next to paracrine acting <em>factors</em>, epidermal homeostasis is controlled by mutual keratinocyte-<em>fibroblast</em> interaction.

The expression of mRNA for the basic <em>fibroblast</em> <em>growth</em> <em>factor</em> (FGF) gene was examined in seven human gastric carcinoma cell lines and in tissue from 29 gastric carcinomas together with the adjacent normal mucosa. Among the seven gastric carcinoma cell lines, the MKN45 cell line expressed mRNA for the basic FGF gene. Basic FGF protein production was confirmed by flow cytometric analysis and immunohistochemistry. Among the surgical specimens, <em>16</em> (55%) of 29 gastric carcinomas showed higher levels of basic FGF mRNA than the normal mucosa. Interestingly, in scirrhous gastric carcinomas characterized by their fibrous stroma and rapid <em>growth</em>, 9 (69%) of 13, samples examined revealed higher levels of basic FGF mRNA than normal mucosa, whereas only 3 (33%) of the 9 well differentiated adenocarcinomas studied produced similar results. Immunohistochemically, basic FGF protein was localized in tumor cells. These results suggest that basic FGF produced by tumor cells may play an important role in producing fibrosis and angiogenesis in gastric carcinomas.

BACKGROUND

Neuronal plasticity is associated with depression, probably as a result of modified expression of proteins important for cellular resiliency. It is therefore important to establish if and how antidepressant drugs may be able to regulate these mechanisms in order to achieve relevant clinical effects.

OBJECTIVE

We investigated the effects of chronic treatment with agomelatine (an MT(1)/MT(2) receptor agonist and 5-HT(2C) receptor antagonist) on the brain-derived neurotrophic factor (BDNF), fibroblast growth factor (FGF-2), and activity-regulated cytoskeleton-associated protein (Arc).

METHODS

Animals were treated for 21 days with agomelatine, venlafaxine, or a vehicle and sacrificed 1 h (6 p.m.) or 16 h after the last injection (9 a.m.) to evaluate the messenger RNA (mRNA) and protein expression of these neuroplastic markers in the hippocampus and prefrontal cortex.

RESULTS

Agomelatine, but not venlafaxine, produced major transcriptional changes in the hippocampus, where significant up-regulations of BDNF and FGF-2 were observed. Both drugs up-regulated the Arc transcription levels. No effects were observed in the prefrontal cortex. Instead, the levels of BDNF protein were elevated by agomelatine in both regions: the effects of the drug on mRNA levels in the hippocampus and cortex are different, while the effects on the protein seem to have the same cumulative result, suggesting different modulatory mechanisms in the two regions.

CONCLUSIONS

Our data provide new information regarding the molecular mechanisms that contribute to the chronic effects of the new antidepressant agomelatine on brain function. The ability of agomelatine to modulate the expression of these neuroplastic molecules, which follows a circadian rhythm, may contribute to its antidepressant action.

Based on preclinical evidence in animal models, the present study examined the clinical efficacy and safety of recombinant human <em>fibroblast</em> <em>growth</em> <em>factor</em>-2 (rhFGF-2) to accelerate bone repair in a dose-escalation prospective trial. One of three dosages (200, 400 or 800 microg) of rhFGF-2 in a biodegradable gelatin hydrogel was injected during surgery into the osteotomy site of 59 knee osteoarthritis patients undergoing high tibial osteotomy, and 57 of them were monitored for <em>16</em> weeks. The rhFGF-2 dose dependently increased the percentage of patients with radiographic bone union, and decreased the average time needed for such union. The percentages of patients with an absence of pain and full-weight bearing were also greater in the higher dosage groups than in the low dosage group, especially in the clinically critical periods 6, 8, and 10 weeks. Neither blood chemistries nor clinical adverse events were associated with the rhFGF-2 dosages. We therefore conclude that the rhFGF-2 in gelatin hydrogel dose dependently accelerated radiographic bone union of a surgical osteotomy with a safety profile at least at the dosages used, suggesting the clinical efficacy of this agent for bone repair.

The aim of the study is to characterize the signal transduction leading to interstitial fibrosis in the pathogenesis of atrial fibrillation (AF) and atrial remodeling. Samples of the left atrial appendage (LA) from patients with AF showed higher collagen content (73 ± 5 vs. 38 ± 2 μg/mg protein) and 2.5-fold increased collagen crosslinking compared to patients with sinus rhythm (SR). Affymetrix-assays, RT-PCR and western Blot analysis revealed that LA of AF patients are characterized by increased lysyl oxidase (LOX) mRNA (218 ± 42%) and protein (253 ± 11%) expression. This was associated with increased expression of connective tissue <em>growth</em> <em>factor</em> (CTGF), fibronectin and Rac1 activity compared to SR. In neonatal cardiac <em>fibroblasts</em>, the Rac1 specific small molecule inhibitor NSC23766 prevented angiotensin II (AngII) induced upregulation of LOX (214 ± <em>16</em>%) expression. Inhibition of CTGF by siRNA transfections completely inhibited AngII induced LOX expression. The LOX specific small molecule inhibitor BAPN prevented AngII and CTGF induced fibronectin expression. Left atria of transgenic mice with cardiac overexpression of Rac1 (RacET) that develop AF at high age exhibited upregulation of CTGF as well as LOX (187 ± 7%) and fibronectin (627 ± 146%) expression. Atria of RacET showed increased collagen content (28 ± 2 μg/mg protein) and crosslinking (10 ± 0.7) compared to wildtypes (20 ± 0.4 μg/mg protein; 5 ± 0.9). Left atrial myocardium of patients with atrial fibrillation is characterized by increased lysyl oxidase and fibronectin expression as well as collagen cross-linking. In cardiac <em>fibroblasts</em>, Rac1 GTPase mediates upregulation of fibronectin via LOX and CTGF. Inhibition of this signaling pathway may therefore represent a target for the prevention of fibrotic atrial remodeling.

The entry of exogenous <em>fibroblast</em> <em>growth</em> <em>factor</em> 2 (FGF-2) to the cytosolic/nuclear compartment was studied and compared with the translocation mechanism used by FGF-1. To differentiate between external and endogenous <em>growth</em> <em>factor</em>, we used FGF-2 modified to contain a farnesylation signal, a CaaX-box. Because farnesylation occurs only in the cytosol and nucleoplasm, farnesylation of exogenous FGF-2-CaaX was taken as evidence that the <em>growth</em> <em>factor</em> had translocated across cellular membranes. We found that FGF-2 translocation occurred in endothelial cells and <em>fibroblasts</em>, which express FGF receptors, and that the efficiency of translocation was increased in the presence of heparin. Concomitantly with translocation, the 18-kDa FGF-2 was N-terminally cleaved to yield a <em>16</em>-kDa form. Translocation of FGF-2 required PI3-kinase activity but not transport through the Golgi apparatus. Inhibition of endosomal acidification did not prevent translocation, whereas dissipation of the vesicular membrane potential completely blocked it. The data indicate that translocation occurs from intracellular vesicles containing proton pumps and that an electrical potential across the vesicle membrane is required. Translocation of both FGF-1 and FGF-2 occurred during most of G(1) but decreased shortly before the G(1)->>S transition. A common mechanism for FGF-1 and FGF-2 translocation into cells is postulated.

OBJECTIVE

To investigate the expression of tumour necrosis factor (TNF)-like weak inducer of apoptosis (TWEAK) and its receptor fibroblast growth factor inducible 14 (Fn14) in the inflamed synovium of patients with arthritis, as TWEAK blockade has been observed to have a beneficial effect in an animal model of rheumatoid arthritis (RA).

METHODS

Synovial tissue (ST) biopsies were obtained from 6 early, methotrexate-naive patients with RA as well as 13 patients with RA and 16 patients with psoriatic arthritis (PsA) who were matched for treatment and disease duration. Serial ST samples were obtained from a separate cohort of 13 patients with RA before and after infliximab treatment. TWEAK and Fn14 expression was evaluated by immunohistochemistry and digital image analysis.

RESULTS

TWEAK and Fn14 were clearly expressed in ST of patients with RA and PsA. TWEAK expression was significantly higher in RA (sub)lining samples compared to PsA (p = 0.005 and p = 0.014, respectively), but Fn14 expression was comparable. Double immunofluorescence showed TWEAK and Fn14 expression on fibroblast-like synoviocytes and macrophages, but not T cells. Of interest, persistent TWEAK and Fn14 expression was found after anti-TNF therapy.

CONCLUSIONS

TWEAK and Fn14 are abundantly expressed in the inflamed synovium of patients with RA and PsA. This raises the possibility that blocking TWEAK/Fn14 signalling could be of therapeutic benefit in inflammatory arthritis.

BACKGROUND

Angiogenesis is essential for the growth of solid tumors, including head and neck squamous cell carcinoma (HNSCC). Angiogenesis is regulated by angiogenic factors such as vascular endothelial growth factor (VEGF) and VEGF receptors (VEGFRs) 1, 2, and 3 known to be located on vascular endothelial cells (VECs). We hypothesize that VEGFRs are also expressed on HNSCC tumor cells in vitro and in vivo and likely control tumor function in vivo.

METHODS

Immunohistochemical analysis for VEGFR-1 (n = 13), VEGFR-2 (n = 21), and VEGFR-3 (n = 16) was performed on human HNSCC tumor samples. Specimens were analyzed for receptor expression and staining intensity. A cultured oral SCC cell line (SCC-25) and a pharyngeal SCC cell line (FADU) were also studied for receptor expression.

RESULTS

The HNSCC tumor cells expressed VEGFR-1, VEGFR-2, and VEGFR-3 in all specimens evaluated. Staining for all 3 receptors was also found on tumor-associated macrophages and fibroblasts, except that VEGFR-2 was not present on fibroblasts. Staining intensity for VEGFR-1 and VEGFR-2 was significantly higher in tumor cells and macrophages than in VECs stained for the same receptor. Both cultured HNSCC cell lines demonstrated expression of all 3 receptors.

CONCLUSIONS

This represents the first report of all 3 VEGFRs being expressed by HNSCC cells. These findings indicate that VEGF may be an autocrine regulator of tumor cell activity in addition to its known angiogenic effects on VECs. The presence of VEGFRs on tumor-associated macrophages and fibroblasts contributes to the complexity of the VEGF/VEGFR system in human cancer.

A patient with therapy-resistant and progressive systemic sclerosis (SSc) with pulmonary involvement who was treated with imatinib mesylate is described herein. Prior to treatment, pulmonary <em>fibroblasts</em> obtained from the patient were cultured and incubated with imatinib mesylate. Preincubation of the <em>fibroblasts</em> for <em>16</em> hours with 2.5 microg/ml imatinib mesylate efficiently abrogated platelet-derived <em>growth</em> <em>factor</em> BB-induced <em>fibroblast</em> proliferation. Furthermore, transforming <em>growth</em> <em>factor</em> beta1-induced type I collagen gene transcription was blocked. During treatment, the patient's pulmonary involvement stabilized and her skin tightness improved. To our knowledge, this is the first report of a patient with therapy-refractory SSc responding to treatment with imatinib mesylate.

Glucose transporter (GLUT) expression and hexokinase activity are thought to be related to high [18F]-fluorodeoxyglucose (FDG) uptake in tumor cells, but their relative importance is still unknown. To determine which is the predominant <em>factor</em> in FDG uptake in tumor cells, cultured tumor cell lines and a normal cell line were studied in vitro with respect to 2-deoxyglucose (DG) uptake, hexokinase activity, and the initial uptake rate of 3-O-methylglucose (3-O-MG) transport, which is generally accepted as indicating the amount of GLUT expressed on the plasma membrane. In <em>16</em> types of tumor cells and one <em>fibroblast</em> cell line, DG uptake was assessed for 60 min, the initial uptake rate of 3-O-MG transport was measured for 1 min, and total hexokinase activity, including that in the mitochondrial fraction, was determined. Across all <em>16</em> tumor cell lines, there was a significant correlation between DG uptake and 3-O-MG transport (p = 0.0012, F test), but not between DG uptake and hexokinase activity. Hexokinase activity of the tumor cells was comparable to that of the human <em>fibroblast</em> cells in the exponential <em>growth</em> phase. Most tumor cells showed higher DG uptake and 3-O-MG transport than the human <em>fibroblast</em> cells. The results suggest that DG uptake of cultured tumor cells is governed by GLUT expression, which may be a distinct characteristic of the neoplastic process.

BACKGROUND

Biological therapies are a new breakthrough in the treatment of psoriasis and psoriatic arthritis (PsA). Among these, tumour necrosis factor (TNF)-alpha antagonists such as infliximab and etanercept are the most promising as TNF is considered to be essential in driving cytokine cascade at sites of cutaneous and synovial inflammation in this disease.

OBJECTIVE

To evaluate the time-related response of serum cytokine release during infliximab monotherapy and assess serum cytokine levels in order to provide a fast, minimally invasive tool to monitor and/or predict efficacy of anti-TNF-alpha therapy.

METHODS

Twenty patients affected by PsA with Psoriasis Area and Severity Index (PASI) score between 0.4 and 42.8 were treated with infliximab for 30-42 weeks. The assessment of arthritis severity was performed using the American College of Rheumatology (ACR) criteria and ultrasonography evaluation. The treatment schedule consisted of infliximab (5 mg kg(-1) intravenously) at 0, 2 and 6 weeks and every 12 weeks on an individual basis determined by therapeutic results and adverse events reported. At baseline and before every infusion blood samples were taken to assess serum cytokine levels [TNF-alpha, interleukin (IL-6), E-selectin, vascular endothelial cell growth factor (VEGF), fibroblast growth factor (FGF), matrix metalloproteinase (MMP-2)].

RESULTS

Eighteen of 20 psoriatic patients achieved>> 50% improvement and 14 of 20 patients attained>> 75% improvement in the PASI score at 10 weeks. All arthritic patients achieved>> 50% improvement (ACR-50) and 16 of 20 patients attained>> 75% improvement (ACR-75) at 10 weeks. TNF-alpha did not decrease immediately during the first part of the study. A significant decrease was detected at week 12 (P < 0.01). In contrast, IL-6, VEGF, FGF and E-selectin showed significant decreases after early infliximab infusions. PASI was not correlated with TNF-alpha in the serum but was significantly correlated with FGF, VEGF and MMP-2. Treatment was well tolerated and there were no significant adverse events in most patients, other than an urticarial reaction and an autoimmune hepatitis.

CONCLUSIONS

Monotherapy with infliximab has to be considered an efficacious and safe treatment for PsA in comparison with traditional disease-modifying antirheumatic drugs. The resolution of cutaneous and synovial symptoms is not related to TNF-alpha serum levels in the initial phases. Apoptosis may play an important role in the modulation of the inflammatory response.

BACKGROUND

Approximately 200,000 incisional hernias are repaired annually in the United States. The high incidence (11-20%) and recurrence rate (24-54%) for incisional hernias have not changed appreciably in 75 years. Mechanical advances in suture material, incision orientation, and closure technique have failed to eliminate this common surgical complication. A biological approach to acute wound failure may offer a new strategy.

METHODS

A rodent incisional hernia model was used. Seventy rats underwent 5-cm midline celiotomies and were closed with fine, fast-absorbing sutures to induce intentional acute wound failure. Group 1 received no other treatment. The midline fascia in groups 2 and 3 was injected immediately prior to incision with 100 microl of vehicle alone or vehicle containing 1 microg of transforming growth factor beta(2) (TGF-beta(2)). Necropsy was performed on Postoperative Day 28 and the wounds were examined for herniation.

RESULTS

Incisional hernias developed in 88% (35/40) and 79% (11/14) of untreated incisions and those treated with vehicle alone. No hernias formed in the TGF-beta(2)-treated incisions (0/16, P < 0.05). Standard histology and immunohistochemistry demonstrated enhanced macrophage, lymphocyte, and fibroblast chemotaxis and increased collagen I and III production in TGF-beta(2) treated incisions.

CONCLUSIONS

Treatment of abdominal wall fascial incisions with TGF-beta(2) prevented the development of incisional hernias in this rat model. TGF-beta(2) stimulated fascial macrophage and fibroblast chemotaxis as well as acute wound collagen production. A biological approach such as this may reduce the incidence of incisional hernia formation in humans.

OBJECTIVE

Fibroblast growth factor 23 (FGF23) is a phosphaturic factor that is elevated in several diseases associated with hypophosphatemia and rickets. Rickets in the absence of vitamin D deficiency has been reported in African and Asian populations with a low calcium intake but the definition of risk factors has proved elusive. The aim of the study was to characterize the biochemical profile and measure FGF23 in a series of Gambian children who had presented with rickets of unknown etiology and a plasma 25-hydroxyvitamin D (25OHD) above the range typical of vitamin D-deficiency rickets.

METHODS

The 46 patients (30 males, 16 females) had bone deformities typical of rickets and were 1.1-16.4 years old (geometric mean, 3.4 years). Active rickets (on radiographs and/or elevated plasma alkaline phosphatase) was present in 28%. Plasma 25-hydroxyvitamin D was above 20 nmol/l in all patients. Concentrations of plasma FGF23, phosphate and other relevant biochemical analytes were measured in stored samples of fasting, early morning plasma and compared with those measured in samples collected from local children and stored under similar conditions.

RESULTS

The rickets patients had lower plasma phosphate, lower 25-hydroxyvitamin D, higher 1,25-dihydroxyvitamin D and elevated total alkaline phosphatase than local children. Those with active rickets had raised parathyroid hormone concentration. The patients had significantly higher FGF23 concentration than local children (geometric mean (-1SD, +1SD, range) RU/ml: 367 (87, 1552, 46-7052, n=39) vs 51 (23, 112, 3-130, n=30), p<or=0.001). At presentation, the majority (74%) had an FGF23 concentration that was above the range seen in local children, some grossly so (up to 50-fold). There was no significant difference in FGF23 concentration between those with active rickets and the other patients. Plasma phosphate was significantly and inversely correlated with FGF23 concentration. Some clinical improvements were noted after 6-12 months, during which time calcium and vitamin D had been prescribed, but FGF23 remained elevated in many patients.

CONCLUSIONS

These data suggest that perturbations of phosphate and FGF23 regulation may be implicated in the pathogenesis of calcium-deficiency rickets in Africa and Asia.

BACKGROUND

Activated receptor tyrosine kinases bind downstream effector molecules with high affinity. Provided that they can be introduced into cells, peptides corresponding to these high-affinity sites should be able to compete for the interaction and thereby inhibit specific signal transduction cascades. The high-affinity binding site for phospholipase C gamma (PLCgamma) on the activated <em>fibroblast</em> <em>growth</em> <em>factor</em> receptor (FGFR) is centred around the tyrosine at position 766 (766Tyr), and peptides corresponding to this site inhibit PLCgamma binding to the receptor in vitro. A <em>16</em> amino-acid peptide from the third helix of the Antennapedia homeodomain protein has recently been shown to be able to act as an internalization vector that can deliver other peptides into cells. Here, we have designed a peptide that contains both the internalization sequence and the FGFR high-affinity binding site for PLCgamma, and tested it in cultures of cerebellar neurons for its ability to inhibit the activation of PLCgamma by basic FGF.

RESULTS

The peptide containing the FGFR high-affinity binding site for PLCgamma inhibited phospholipid hydrolysis stimulated by basic FGF with a maximal effect at 1 microg ml-1. Phosphorylation of 766Tyr was required for this effect. The phosphorylated peptide had no effect on phospholipid hydrolysis stimulated by platelet-derived growth factor, neurotrophin-3 and bradykinin. The phosphorylated peptide also inhibited neurite outgrowth stimulated by FGF, but had no effect on neurite outgrowth stimulated by agents that activate the FGFR signal transduction cascade downstream from the activation of PLCgamma.

CONCLUSIONS

Cell-permeable peptides can be designed that inhibit the function of receptor tyrosine kinases. In this context we have developed a peptide that prevents the FGFR from activating PLCgamma, and have used this peptide to obtain the first direct evidence that activation of PLCgamma is required for the neurite outgrowth response stimulated by basic FGF.

Treatment of human <em>fibroblasts</em> with epidermal <em>growth</em> <em>factor</em> (EGF) results in a rapid increase (less than 5 min) in the ability of the cells to bind 125I-labeled transferrin to surface receptors. Scatchard analyses of EGF-treated cells indicate that this increase was due to an increase in the number of transferrin receptors at the cell surface rather than to alterations in ligand-receptor affinity. The EGF-induced increase in transferrin receptors was transient, reaching a peak by 5 min and then declining back to near basal levels by 45 min. Increases in transferrin receptor number were observed when approximately equal to 1% of the EGF receptors were occupied and were maximal at <em>16</em>% occupancy. EGF treatment accelerated the rate at which previously internalized 125I-labeled transferrin-receptor complexes were returned to the cell surface. The kinetics and magnitude of the loss of intracellular transferrin receptors was sufficient to account for the increase in surface transferrin receptors. We conclude from these studies that one of the earliest effects of EGF treatment is the induced translocation of an intracellular compartment to the cell surface. This intracellular compartment contains transferrin receptors and may be part of the pathway involved in the normal recycling of cell surface proteins.

Dyskeratosis congenita (DC) is characterized by the triad of reticulate skin pigmentation, nail dystrophy and leukoplakia. Epidermal atrophy, hair <em>growth</em> defects, bone marrow failure and increased risk of cancer are also common in DC patients. DC is caused by mutations in genes encoding for telomerase complex <em>factors</em>. Although there is an association of epidermal abnormalities with DC, epidermal cells from DC donors have not been previously characterized. We have isolated skin keratinocytes from affected members of a family with an autosomal dominant form of DC that is caused by a mutation in the RNA component of telomerase, TERC. Here, we demonstrate that, similar to DC <em>fibroblasts</em> from these donors, DC keratinocytes have short telomeres and a short lifespan. DC keratinocytes also exhibited impaired colony forming efficiency (CFE) and migration capacity. Exogenous expression of the reverse transcriptase (RT) component of telomerase, TERT, activated telomerase levels to half that of TERT expressing normal cells and maintained telomeres at a short length with concomitant extension of lifespan. Unlike <em>fibroblasts</em>, transduction of human papillomavirus type <em>16</em> E6/E7 genes into DC keratinocytes activated telomerase to half that of E6/E7 expressing normal cells, and robust proliferation was observed. While expression of TERC has no measurable effect on telomerase in <em>fibroblasts</em>, expression of TERC in keratinocytes upregulated telomerase activity and, rarely, allowed rescue of proliferative defects. Our results point to important differences between DC <em>fibroblasts</em> and keratinocytes and show, for the first time, that expression of TERC can increase the lifespan of primary human epithelial cells.

Upregulation of acidic and basic <em>fibroblast</em> <em>growth</em> <em>factors</em> (FGF-1 and -2), and their cognate receptors FGFR-1 and -2, has been demonstrated in a variety of epithelial malignancies. However, the patterns of FGF/FGFR expression at specific stages of epithelial carcinogenesis have not been extensively characterized. In this report, the levels of FGF-1, FGF-2, FGF-7 mRNA and their receptors FGFR-1 and FGFR-2, were investigated during epidermal carcinogenesis in transgenic mice expressing the early region of the 'high risk' papillomavirus type <em>16</em> (HPV<em>16</em>) under control of the human keratin-14 enhancer/promoter (K14-HPV<em>16</em> transgenic mice). FGF-1 was first upregulated in dysplasias, while FGF-2 was constitutively expressed in non-transgenic, neoplastic, and malignant keratinocytes throughout carcinogenesis. Expression of FGF-7 was undetectable in non-transgenic epidermis, and remained at threshold levels at all stages of progression. In well differentiated squamous cancers, FGFR-1 was upregulated and co-localized with angiogenic capillaries in the dermis underlying dysplastic lesions and within papillary fronds of invasive cancers. In contrast, FGFR-1 was upregulated specifically within the malignant squamous cells of moderate-poorly differentiated squamous cancers. The expression of FGFR-2 was essentially constitutive in both non-transgenic and neoplastic epidermis. Collectively the data suggest that the FGF/FGFR signaling pathways may potentially contribute to several facets of multi-stage epithelial carcinogenesis, including auto- or paracrine <em>growth</em> stimulation, upregulation of angiogenesis, and stromal remodeling.

Potentially 96 splice variants among four genes that code for the human heparin-binding <em>fibroblast</em> <em>growth</em> <em>factor</em> receptor family complicate study of structure, metabolism, and function of single isoforms in mammalian cells. As an alternative, we expressed structural subdomains and isoforms of the flg receptor gene in bacteria and baculoviral-infected insect cells. We developed and characterized a panel of <em>16</em> isoform and domain-specific polyclonal and monoclonal antibodies. The panel of antibodies was used to distinguish mature glycosylated ligand-binding and kinase-active and -inactive recombinant isoforms in baculoviral insect cells and transfected mammalian cells and natural isoforms in rat prostate and human liver cells. The results revealed a cell type-specific expression of the flg gene and isoforms that result from combinations of splice variations. Reactive epitopes of monoclonal antibodies against both the three (alpha) and two (beta) immunoglobulin-like disulfide loop extracellular domain isoforms were mapped by cross-reactivity with synthetic polypeptide sequences and deletion mutants expressed in bacteria. The native alpha and beta receptor isoforms differed in display of shared epitopes and suggested that the NH2-terminal Loop I and COOH-terminal Loops II and III of the alpha isoform are interactive. Although the common Loops II and III appear qualitatively sufficient for ligand binding, the results suggest that tertiary relationships among loops in the three and two loop isoforms are distinct and, therefore, the two isoforms may have distinct activities. Spatial models for arrangement of immunoglobulin-like loops in the extracellular domain of the two isoforms are presented.

Basic <em>fibroblast</em> <em>growth</em> <em>factor</em> (bFGF; FGF-2) lacks a signal sequence and thus is not secreted by classical pathways. It has been speculated that one mode of bFGF release may be injury, either sublethal or lethal; and, transient disruption of the plasma membrane has been shown to release bFGF [Muthukrihnan et al. (1991): J Cell Physiol 148:1-<em>16</em>]. This observation has led to the concept of bFGF as a "wound hormone," involved in tissue integrity and repair. Findings of elevated bFGF following injury in vivo support this concept. Using an in vitro model, we have examined the regulation of bFGF gene expression following its release by sublethal injury. Analysis of bFGF protein by ELISA revealed that scraping subconfluent bovine aortic EC (BAE) released up to 80% of their bFGF. Following scraping, there was a 4- to 10-fold increase in the steady state level of bFGF mRNA, which reached a maximum at 2-3 h. There was a parallel increase in protein so that by 6 h after the scrape-induced release, bFGF levels were restored to those measured prior to scraping. Since bFGF has been reported to induce its own expression, we hypothesized that the released bFGF might be responsible for the increase in bFGF mRNA. However, inclusion of neutralizing antibodies against bFGF had a negligible effect on the scrape-induced increase in bFGF mRNA levels. Because of the important role of transforming <em>growth</em> <em>factor</em> type-beta 1 (TGF-beta 1), the plasminogen/plasminogen activator system, and thrombin in wound healing, we investigated their potential contributions to the increase in bFGF expression. Addition of anti-TGF-beta 1 antibodies, plasminogen activator inhibitor-1 (PAI-1), or the thrombin inhibitory combination of heparin and anti-thrombin III (AT III) to the cells at the time of scraping blocked about 50% of the increase in bFGF mRNA; the effects of these agents were not additive. The suppression of bFGF mRNA was associated with a proportional reduction in bFGF protein. Inclusion of the antagonists for 2 h at the time of scraping led to reduced cell proliferation, suggesting that cell-associated bFGF may be required for recovery and <em>growth</em>. Finally, studies to characterize the molecular mechanisms underlying the increased bFGF mRNA following sublethal injury revealed an increase in the transcriptional activation of bFGF gene. These results indicate that in spite of the fact that bFGF is not a secreted protein, levels of bFGF in the cell are tightly regulated. Furthermore, these findings suggest a role for bFGF in recovery from cell injury.

Various genetic mutations associated with cancer are known to alter cell signaling, but it is not clear whether they dysregulate signaling pathways by altering the abundance of pathway proteins. Using a combination of RNA sequencing and ultrasensitive targeted proteomics, we defined the primary components-<em>16</em> core proteins and 10 feedback regulators-of the epidermal <em>growth</em> <em>factor</em> receptor (EGFR)-mitogen-activated protein kinase (MAPK) pathway in normal human mammary epithelial cells and then quantified their absolute abundance across a panel of normal and breast cancer cell lines as well as <em>fibroblasts</em>. We found that core pathway proteins were present at very similar concentrations across all cell types, with a variance similar to that of proteins previously shown to display conserved abundances across species. In contrast, EGFR and transcriptionally controlled feedback regulators were present at highly variable concentrations. The absolute abundance of most core proteins was between 50,000 and 70,000 copies per cell, but the adaptors SOS1, SOS2, and GAB1 were found at far lower amounts (2000 to 5000 copies per cell). MAPK signaling showed saturation in all cells between 3000 and 10,000 occupied EGFRs, consistent with the idea that adaptors limit signaling. Our results suggest that the relative stoichiometry of core MAPK pathway proteins is very similar across different cell types, with cell-specific differences mostly restricted to variable amounts of feedback regulators and receptors. The low abundance of adaptors relative to EGFR could be responsible for previous observations that only a fraction of total cell surface EGFR is capable of rapid endocytosis, high-affinity binding, and mitogenic signaling.

It has been recently demonstrated that histone deacetylase inhibitors inhibit angiogenesis, but their mechanism of action has not been characterized well. In this study, we examined the in vitro and in vivo effects of FK228 [(E)-(1S,4S,10S,21R)-7-[(Z)-ethylidene]-4,21-diisopropyl-2-oxa-12,13-dithia-5,8,20,23-tetraazabicyclo-[8,7,6]-tricos-<em>16</em>-ene-3,6,9,19,22-pentanone; FR901228, depsipeptide], an HDAC inhibitor, on the expression of angiogenesis <em>factors</em> in FK228-sensitive PC-3 prostate and FK228-resistant ACHN renal cancer cells. FK228 suppressed the expression of VEGF mRNA in PC-3 cells, but not in ACHN cells. FK228 also suppressed the expression of basic <em>fibroblast</em> <em>growth</em> <em>factor</em> (bFGF) mRNA in both PC-3 and ACHN cells. Under conditions of hypoxia, FK228 suppressed the expression of VEGF mRNA without modulating the expression of hypoxia-inducible <em>factor</em>-1 alpha mRNA in PC-3 cells. FK228 induced the highest acetylation of histone H3 and H4 in the P2 region of the VEGF promoter, which includes the hypoxia-inducible <em>factor</em>-1 alpha binding site that plays an important role in regulating the expression of VEGF gene. Moreover, FK228 reduced the amount of VEGF and bFGF protein, and their mRNA levels in PC-3 xenograft implanted in nude mice, but did not reduce them in ACHN xenograft.

CONCLUSIONS

(i) FK228 showed a suppressive effect on the expression of angiogenesis factors, such as VEGF and bFGF, in PC-3 xenograft but not in ACHN xenograft, which suggests that the effect on the expression of angiogenesis factors is important for the antitumor efficacy of FK228; (ii) FK228 caused histone acetylation of the VEGF promoter regions, which may contribute to the suppression of VEGF gene expression.

OBJECTIVE

The purpose of this study was to analyze the possible correlation between PEA3 mRNA expression and survival in advanced-stage ovarian carcinomas, studying two patient groups with extremely different disease outcome.

METHODS

Sections from 61 primary ovarian carcinomas and metastatic lesions from 36 patients diagnosed with advanced-stage ovarian carcinoma [International Federation of Gynecologists and Obstetricians (FIGO) stages III-IV] were evaluated for expression of PEA3 using mRNA in situ hybridization. Patients were divided into long-term (n = <em>16</em>) and short-term (n = 20) survivors.

RESULTS

The mean values for disease-free survival and overall survival were 119 and 137 months for long-term survivors, as compared with 4 and 22 months for short-term survivors, respectively. Expression of PEA3 mRNA was detected in carcinoma cells and stromal cells in 56 of 61 lesions (92%) and 54 of 61 lesions (89%), respectively. Intense stromal expression was detected only in the vicinity of grade 2-3 tumors (P = 0.04). PEA3 expression in stromal cells showed a significant association with matrix metalloproteinase 2 mRNA expression in carcinoma cells (P = 0.022). PEA3 expression in carcinoma cells showed an association with mRNA expression of the beta(1) integrin subunit in the same compartment (P = 0.039). It was also associated with mRNA expression of beta(1) integrin subunit (P = 0.012), basic fibroblast growth factor (P = 0.036), and the matrix metalloproteinase inducer EMMPRIN (P = 0.038) in stromal cells. PEA3 mRNA was detected more often in both carcinoma and stromal cells in tumors of short-term survivors (P = 0.021 for stromal cells). In univariate survival analysis, PEA3 expression in stromal cells correlated with both shorter disease-free survival (P = 0.019) and overall survival (P = 0.029), whereas tumor cell expression predicted poor overall survival (P = 0.049). PEA3 mRNA expression in stromal cells emerged as an independent predictor of poor outcome in multivariate survival analysis, in which all molecules previously studied in this patient cohort were included (P = 0.015).

CONCLUSIONS

To the best of our knowledge, this is the first evidence associating PEA3 mRNA expression and poor survival in human epithelial malignancy. PEA3 is thus a novel prognostic marker in advanced-stage ovarian carcinoma. The association between PEA3 mRNA expression and the expression of the beta(1) integrin subunit, basic fibroblast growth factor, and EMMPRIN, first documented in our patient cohort, points to the central role of this transcription factor in tumor progression in ovarian carcinoma.